Stoker apparatus



NOV 29, 1955 w. KEssLi-:R

STOKER APPARATUS Filed Feb. 14, 1951 INVENTOR Wilbur Kessler r mm. Hilf ATTORN EY United States Patent O 2,725,021 sToKER APPARATUS Wilbur Kessler, Broomall, Pa., assignor, by mesne assignments, to Detroit Stoker Company, a corporation of Michigan Application February 14, 1951, Serial No, 210,917

6 Claims. (Cl. 110-40) This invention relates to combustion apparatus, more particularly to traveling grate stokers, and has for an object to provide improved sealing means therefor.

Where the grate of a traveling grate stoker comprises a plurality of endless bolt assemblies of grate bars with the assemblies arranged in side-by-side relation, a limited space must be left between adjacent terminal portions of the grate bars of adjacent assemblies, to provide for growth of the iron bars without rubbing or binding.

At the same time it is important that excessive passage of air, through such limited spaces,from the plenum chamber therebelow, be prevented, and it is an object of the present invention to provide novel means for sealing such spaces against excessive air flow.

In accordance with the invention, the same sealing means is utilized at similar spaces between the outside assemblies of grate bars and the adjacent stationary structure of the furnace side walls.

Yet another object of the invention is to provide means for biasing the sealing means into sealing engagement with the grate bars and furnace side wall structure.

Another object of the invention is to provide means for temporarily overcoming the biasing force applied to the sealing means by the biasing means.

These and other objects are eifected by the invention as will be apparent from the following description and claims taken in connection with the accompanying drawings, forming a part of this application, in which:

Fig. l is a longitudinal sectional view of a traveling grate stoker incorporating the present invention;

1Eig. 2 is a sectional view, taken along the 'line Il-ll of Fig. 1, looking in the direction indicated by the arrows; and,

Pig. 3 is an enlarged fragmentary perspective view of one of the grate bars.

Referring now to the drawings in greater detail, the reference character 1G indicates, in its entirety, a traveling grate stoker installed in a furnace 11 having a front wall 12, rear wall 13, and side walls 14.

Front and rear shafts 15 and 16, respectively, extend transversely of the furnace and carry a plurality of pairs of sprockets 17. The sprockets on the front shaft 15 are aligned with those on the rear shaft 16, longitudinally of the stoker and each pair of longitudinally-aligned sprockets carries an endless chain 18.

A pair of spaced parallel horizontal structural members 19 extend longitudinally of the Stoker below the upper run of each chain 18 (Fig. 2) and have mounted therebetween a series of rollers 21, each roller including a peripheral chain-guiding rib or flange 22 anked by peripheral chain-supporting surfaces 23, so that the upper run of each chain 18 is supported, intermediate the sprockets 17, by the rollers 21.

Attached to each pair of chains 18 are a multiplicity of grate bars 2S, of a length materially greater than the spacing of the chains, so that the bars 25 not only bridge the space between the chains, but have their terminal portions l26 extending beyond the chains.

The particular construction of the grate bars 25, and their mode of attachment to the chains 18, form no part of the present invention, being covered by applicants copending application Serial No. 210,714, filed February 13, 1951, for Stoker.. Apparatus, now Patent No. 2,666,404, dated January 19, 1955, and assigned to the assignee of the present application. For a detailed description of the grate bars 25, reference may be had to the above-mentioned copending application.

As best shown in Fig. 2, the terminal portions 26 of the adjacent grate bars of adjacent pairs of chains are slightly spaced, as at 30. Similarly, the terminal portions 26 adjacent the furnace side walls 14 are slightly spaced, as at 31, from stationaryrmembers 32 forming a part of the furnace side walls. These spaces and 31 provide for thegrowth of the iron grate bars, which occurs during their continued use. If such spaces were not provided, the bars would abut end to end and bind against each other and the furnace side wall members 32.

Therefore, while these spaces 30 and 31 are essential to satisfactory oper'ation of the` traveling grate, they would, unless sealed, permit an excessive ow of air therethrough from the pressurized plenum chamber 34 below the grate to the combustion space 35 thereabove.

To seal the spaces 30 and 31 applicant provides channel members 36 positioned beneath the spaces in sealing engagement with depending flanges v37 carried by the grate bar terminal portions 26 and similar depending flanges 38 carried by the furnace side wall members 32.

In order to bias the channel members 36 into sealing engagement with the depending anges 37 and 38, the members 36 are provided with longitudinally-spaced depending pairs of links 39 connected at their lower ends with the short arms 40 of fulcrum levers 41 fulcrumcd on pins 42. Weights 43 are carried by the free ends of the long arms 44 of the levers 41, providing the forces necessary to bias the sealing members against the depending flanges.

At times it may be desirable to relieve the sealing members 36 of the forces biasing them against the grate bars, as for example, when removing or replacing a grate bar. To this end, there may be provided cables 50 extending from the lower ends of the links 39, over pulleys 51 and 52, to a point exterior of the furnace, where necessary tension may be applied to move the sealing members away from the grate bars.

While the invention has been shown in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof.

What is claimed is:

l. In a traveling grate Stoker, a pair of horizontal shafts near opposite ends of the stoker; a pair of axiallyspaced sprockets on each of said shafts, the sprockets on one shaft being aligned with those on the other shaft longitudinally of the Stoker; an endless chain carried by each pair of longitudinally-aligned sprockets; a multiplicity of transversely-extending grate bars carried by the pair of chains and bridging the space between the latter with their terminal portions extending beyond the pair of chains; vertically stationary means supporting the upper run grate bars intermediate their ends; movable sealing structure engaging the lower edges of the upper run grate bar terminal portions; and means biasing said movable sealing structure upwardly into contact with said grate bar terminal portion lower edges.

2. In a traveling grate stoker, a pair of parallel horizontal transversely-extending shafts near opposite ends of the stoker, a pair of axially-spaced sprockets on each of said shafts with the sprockets on one shaft aligned with those on the other shaft, an endless chain carried by each pair of aligned sprockets, a multiplicity of transverselyextending Agrate bars rcarried by the pair of chains and bridging the space therebetween with their terminal portions extending 'beyondthe pair'of chains, means supporting the upper runs of the chains intermediate the sprockets whereby the grate bars carried by said upper runs yare also supported, v,a stationary air-sealing structure adjacent one'termnal portion of the grate bars ofthe upper run, movable `sealing means abutting the stationary air-sealing structure and the adjacent terminal portions of the upper run grate bars in bridging sealing relation to the joint therebetween, and means for biasing the movable sealing means into sealing engagement with said stationary air-sealing structure and said upper run grate bar terminal portions.

3. In a traveling grate stoker, a pair of parallel-transversely-extending .shafts near opposite ends of `the stoker, a plurality of pairs of kaxially-spaced sprockets on each of said shafts with the sprockets on one shaft aligned 1ongitudinally of the stoker with the sprockets on the other shaft, an endless chain carried by each longitudinallyalignedpair of sprockets, a multiplicity of transverselyextending grate bars carried by each pair of chains and bridging the space therebetween with their terminal portions extending beyond the chains of each 4pair into slightly-spaced `proximity to the terminal portions of grate bars carried by adjacent pairs of chains, vertically-movable sealing members bridging the spaces between vthe slightly-spaced terminal portions of the grate bars of adjacent .pairs of Chains, and means for biasing said vertically-movable sealing members into sealing engagement with said terminal portions.

4. In a traveling grate Stoker, a pair of parallel horizontal transversely-extending shafts nearopposite ends of the stoker, Va plurality of pairs of axially-spaced sprockets on each of said shafts with the sprockets on one shaft aligned longitudinally of the stoker with the sprockets on ytheother shaft, an endless chain carried by each longitudinally-aligned pair of sprockets, a multiplicity of transversely-extending grate "bars carried by each pair of chains and bridging the space therebetween with their terminal portions extending beyond the chains of each pair into slightly-spaced proximity to the terminal portions of grate bars carried by adjacent pairs of chains and to side wall structure of lea furnace in which the stoker is operated, vertically-movable sealingmembers bridging the spaces between the slightly-spaced terminal portions of the ygrate bars of'adjacentpairs of chains, and between the grate bar terminalportions,andiadjacent furnace side wall structure, and means for biasing said verticallymovable sealing members into sealing engagement with said terminal portions and said furnace side wall structure.

5. Structure as specified in claim 4, wherein the biasing means comprises fulcrumed levers, means joining one arm of each `lever to a Asealing member, and a weight carried b y the other arm of each lever, whereby the force of the weight acting through the fulcrumed lever acts on the sealing member to bias itinto sealing engagement.

6. kStructure as specified in claim 5, including means for .applying to each fulcrumed lever a force over balancing the force applied by the weight, whereby the sealing members may be temporarily unbiased.

IReferences Cited in the tile of this patent UNITED STATES PATENTS 1,339,531 Wallen May 1l, 1920 `1,653,113 Magee Dec. 20, 1927 1,660,217 Bennis Feb. 21, 1928 1,832,888 Zinkernagel Nov. 24, 1931 FOREIGN PATENTS 220,734 Great Britain Aug. 28, 1924 

